Facebook chief Mark Zuckerberg will sell a chunk of his stake in the company, cashing in some $US2.3 billion ($A2.61 billion), as part of a new share offering by the huge social network.
A Facebook filing on Thursday said the company would sell 70 million shares in a follow-on offering to the huge initial public offering in May 2012.
Of the total amount, Zuckerberg will sell around 41 million shares, mainly to satisfy his tax obligations, the company said in a statement.
The 27 million new shares at Facebook's latest closing price of $US55.57 would raise some $US1.5 billion for the company "for working capital and other general corporate purposes," the statement said.
Zuckerberg's sale will have little impact on his control of the company he co-founded from his Harvard University dormitory.
He owns an estimated 29 per cent of Facebook capital, but based on the dual classes of stock, he will still hold 56.1 per cent of the voting rights after the new offering, down from 58.8 per cent.
With the proxies he holds for other shareholders, Zuckerberg will control 62.8 per cent of the voting rights after the new offering, down from 65.2 per cent.
The company said Zuckerberg will exercise his option to purchase 60 million Class B shares, which have 10 voting rights, and then convert the shares to Class A, which have one voting right, for the sale.
Another early Facebook investor, entrepreneur Marc Andreessen, will sell some 1.6 million shares in the offering.
The filing with the Securities and Exchange Commission also notes that Zuckerberg plans to donate 18 million shares to an unspecified beneficiary.
He and his wife Priscilla last year gave a similar amount to a Silicon Valley foundation.
One of the reasons for the new Facebook offering is to meet expected demand with Facebook being added to the Standard & Poor's 500 index. That requires portfolio managers who own the stock index to buy Facebook shares.
Being added to the S&P 500 comes at the end of a year in which Facebook climbed out from the wreckage of its much-hyped, but quickly panned, stock market debut early in 2012.
Facebook has been on an upward cycle since earnings showed a jump in mobile advertising revenue.
Zuckerberg's net worth was estimated by Forbes magazine at $US19 billion at the end of September, making him the 25th richest person in the United States and 66th wealthiest in the world.
Facebook stock fell by more than half after the 2012 IPO at $US38, but have doubled since August and hit record highs in recent weeks.
In early trade on Thursday, the stock was down 1.6 per cent at $US54.65.
The world's leading online social network reported profit of $US425 million in the quarter that ended on September 30, compared with a loss a year earlier, while revenues rose sharply to $US2.016 billion
